This article explores the federal marine hospitals of the early republic, the first public health care system in US history. Beginning in 1798, the federal government collected twenty cents per month from mariners' wages and used this revenue to subsidize medical care for sick and disabled merchant mariners. Previous studies have traced links between marine hospitals and modern public policy. By studying governance from the bottom up, this article takes a different approach. I argue that jurists, physicians, and officials' regulation of sailors' entitlement to public health care facilitated and reflected a transformation of national authority. Between 1798 and 1816, sailors' entitlement was a local matter, based on the traditional paternalist understandings of maritime laborers as social dependents. By 1836, though, the federal Treasury redefined entitlement around a newly calculus of productivity: only the productive were entitled to care at the marine hospitals. This story about governance, federal law, and political economy in the early United States suggests that the early American state was a more vibrant participant in the market and society than has been previously understood.